Combustion turbine



@t 24, 1933. H. HoLzwAR'n-l 1,931,545

COMBUSTION TURBINE mea Nov. 27. 192s jnvenior: 4A/5 /OL z Mmm Patented oei. 24, 1933 COMBUSTION TUBBINE Hans Holzwarth, Dusseldorf, Germany, assignor to Holzwarth Gas Turbine Co., San Francisco, Calif., a corporation of Delaware Application November 27, 1928, Serial No.

322,154, and in Germany December 9, 1927 1 Claim.` (Cl. (iO-41) Compound explosion turbines as heretofore proposed by me have generally been so constructed that the combustion gases of high temperature discharging fromv the combustion chambers 5 forming part of the turbine were nrst directed against a Curtis wheel having two or more sets of blades and forming the high pressure stage of the turbine, and were then conducted to a continuous current multistage pressure turbine of the Parsons type. Before the gases discharging from the Curtis wheel were conducted to the second stagewhich in general was constructed as a separate intermediate or low pressure turbine unit, the temperature thereof was considl5 erably reduced by means of cooling steam. This `reduction in the temperature of the exhaust l gases was necessary because the turbine systems i. e. Parsons turbines, which were used in the intermediate or low pressure units were not suited to operate withuncooled combustion gases.

Cooling by means of steam was formerly employed also in the high pressure stage of a multistage combustion gas turbine; however, after a material for the rotor blades was found which could withstand the high temperature of the gases as they issuevfrom the combustion chambers, cooling of the gases in the high pressure stage by means of steam. was dispensed with. The'necessity of steam cooling of the stages following the high pressure stage has, however, always been apparent, since multistage turbines are not adapted to withstand high admission temperatures on account of their great structural length and the small packing clearances inherent in such turbines, and on account of the fact that it is impractical to build bulky machines of thistype of extremely expensive heat resisting alloys, and therefore the necessity of cooling the explosion gases or the turbines with steam was unquestioned. Hence a cumbersome and expensive arrangement resulted.

The present invention relates to a constant volume explosion turbine system constructed with the above indicated problem in view and solves the same by arranging Curtis wheels in pressure stages. The invention therefore foll lows the teaching gained in steam turbine construction to the effect that Curtis wheels are ablel to withstand the most highly superheated steam and therefore are highly suited to take advantage of the high pressure drop. The Curtis wheels of the second and the following stages of an explosion turbine can therefore be directly operatedwlth the gases of high temperature which have done work in the high pressure stage, i. e. without previous cooling of such gases, so that the necessity of steam cooling is obviated and this, together with the disk-wheel construction of the Curtis rotor bodies, permits the weight to be reduced to within practicable limits. The present invention involves, however,

a radical departure from prior explosion gas turbine theory and practice. In the endeavor to obtain as high an efficiency as possible, both for stationary and portable plants, it had heretofore been regarded as essential that the second or low pressure stage of the explosion turbine plant be built in the form of a Parsons turbine because, as is well known, the eiilciency of such I turbine is considerably higher than that of a Curtis or velocity wheel. I have found, however, that under the peculiar conditions existing in an explosion gas turbine, a Curtis wheel can utilize uncooled gases at an eliiciency which is not materially lower, and may even be considerably higher than the eiilciency of a, Parsons turbine operating with cooled gases. My invention thus provides a power plant which in eiliciency is generally at least as good as a plant utilizing a multistage pressure turbine, and in addition,

is smaller in size, lighter in weight and considerably less expensive to build.

The Curtis wheels may have two and even more velocity stages in order to be able to make use of the velocity drop without loss. If collecting chambers are provided between the individual pressure stages, which chambers operate to equalize the pressure of the combustion gases and to reduce the whirling motion thereof, then the operation of the subsequent Curtis wheels is effected by a continuous stream of gas, even though the combustion itself is of the intermittent explosion type. The Curtis wheel housings of the individual pressure stages are sealed from one another by arranging labyrinth packings about' the sections of the shaft located between the Curtis wheels, the spacing of the latter depending on the arrangement of the collecting chambers.' If of two or more Curtis wheels connected to the same shaft one is struck intermittently by iets of explosion gases, and thereby subjected to sudden impacts, while the other or others are struck by a more or less steady stream of gas due to the arrangement of a collecting or equaliz'ing chamber in the path 105 of the gases discharging from the first wheel, the shaft section between any two wheels, because of the peculiar stresses imposed thereon, must be specially constructed in order to prevent torsional and bending distortions and the resulting irregular rotation, increase in the gap losses, etc. In a further development of the invention the shaft is made of a diameter nearly half that of the Curtis wheels attached thereto and therefore a multiple of that required by the moment of rotation to be transmitted.

The drawing shows by way of example an embodiment of the inventive idea without defining its limits, the view being yan elevation partially in section of a two stage explosion turbine.

After the combustion or explosion has taken place in the well-known manner, for example, in the explosion chamber a1, the `combustion gases so generated, upon opening of the exhaust valve b1, 'flow through the connecting channels c1 and nozzle d1 and are discharged by the latter against the high pressure Curtis wheel e having two sets of blades. The direction of the gases through the wheel e is reversed by the stator blades f in a manner well understood in the art. After performing work in this high pressure stage of the turbine, the gases flow into an annular collecting space g in which equalization of the pressure and quieting of the whirling takes place. The gases then travel through the connecting channel h and nozzle i and strike the Curtis wheel lc of the second stage in the form of a continuous current, the latter wheel being likewise formedy of two sets of blades, the reversal of the gas streams being effected by the stator blades Z. The combustion gases which, so far as their capacity for performing mechanical work is concerned, have been completely deenergized, collect in the annular space m, from which they are withdrawn through the conduit n for further use.

As the drawing clearly indicates, the diameter of the shaft o between the two Curtis wheels e and 1c, which are disk-like in form, is equal to almost half the diameter of either of these wheels and is therefore several times the diameter ,which is required by the moment' of ro-` rectly to the second Curtis wheel in a continu-l tation to be transmitted. In this way the possibility of torsional and bending distortion is avoided, which, as is well known, cause irregular running of the turbine rotor, increase in the gap losses, and other disadvantages. Labyrinth packings p1, p2, p3, and p4 seal the Curtis wheel housing towards the outside, while the labyrinth packing p5 of the shaft section o located between the Curtis wheels e and 7c, which are spaced from each other by a distance which depends on the arrangement of the collecting chamber g, seals the Curtis wheel housings q and r of both pressure stages from each other. In the turbine housing itself, other special cooling spaces s, t, u, v, w, y and z are provided which transfer the heat taken up by the walls of such housing to a cooling medium, preferably water or oil. By the arrangement of the cooling space s, w and :c an almost complete cooling of the turbine wheel disks e and Ic is obtained. The several cooling spaces may be connected with each other by means of connecting conduits; for instance, the conduit v' may connect the cooling space o with the cooling space w.

The plant may include a plurality of explosion chambers (note also chamber a), such chambers being of the constant Volume type of known construction (see my United States Patents Nos. 877,194 and 1,672,529). The chambers are provided with fuel and air .inlet valves and with igniting means of known construction which are controlled in predetermined timed sequence in any suitable manner (see the control mechanism in my above-mentioned Patent No. 877,- 194). As these elements form nopart of the present invention, it is not necessary to illustrate them.

Variations may be resorted to within the scope of the appended claim without departing from the spirit of the invention.

I claim:

An explosion turbine, comprising, in combination, a valve controlled explosion chamber adapted to be charged with an ignitable mixture for explosion therein at constant Volume, a periodically operated nozzle valve adapted to eiect intermittent discharge of the explosion gases from said chamber, a Curtis wheel arranged to be struck by the intermittent jets of explosion gases, a second Curtis wheel, and means for conducting the hot gases exhausting under pressure from the first Curtis wheel dious stream without substantial cooling of the gases including a collecting and equalizing chamber arranged to receive the gases exhausting from the intermittently impinged first Custis wheel and operative to establish an intermediate pressure at which the intermittently and `continuously impinged Curtis wheels develop their proportionate capacities.

HANS HOLZWARTH. 

